Rotor coupling anti-windage apparatus

Abstract

An anti-windage device is provided for use on the couplings formed by mating flanges of rotors for turbomachines, such as steam turbines and the like. The anti-windage device is comprised of upper and lower anti-windage ring segments. The anti-windage ring segments have holes for each of the nuts that are threaded onto the bolts that join the mating flanges into a rotor coupling. The holes enclose the nuts and the anti-windage ring segments fill the circumferential spaces between adjacent nuts. The ring segments are secured to the rotor flange by causing the nuts to bear against an annular lip formed in each hole. The depth of the holes and the axial thickness of the anti-windage ring is such that the end faces of the anti-windage ring, nuts and bolts are flush, thereby forming a smooth surface that minimizes windage.

We claim: 
     
       1. A turbomachine, comprising: a) a rotor having a flange formed thereon for coupling said rotor to another rotor, a plurality of holes formed in said flange;   b) a bolt extending through each of said flange holes, each of said bolts having means for attaching said bolt to said flange; and   c) a ring, attached to said flange, having a hole for each of said attaching means, each of said ring holes at least partially enclosing each of said attaching means for reducing the windage associated with the motion of said attaching means as said rotor rotates.   
     
     
       2. The turbomachine according to claim 1, wherein each of said attaching means comprises a nut. 
     
     
       3. The turbomachine according to claim 1, wherein said ring and each of said attaching means have an end face, said end faces being substantially flush with respect to each other. 
     
     
       4. The turbomachine according to claim 1, wherein each of said holes in said ring has a depth and each of said attaching means has a height, said hole depth being approximately equal to said attaching means height, whereby a surface of said ring is substantially flush with a surface of each of said attaching means. 
     
     
       5. The turbomachine according to claim 4, wherein: a) each of said bolts has an end face that extends a distance beyond said flange;   b) said ring has first and second faces defining a thickness therebetween, said first ring face being disposed against said flange, said thickness being approximately equal to said distance by which said bolt end face extends beyond said flange; and   c) each of said attaching means has an end face; whereby said bolt end faces, said ring second face, and said attaching means end faces form a substantially smooth surface.     
     
     
       6. The turbomachine according to claim 1, wherein said ring has means for being held on said flange by said attaching means. 
     
     
       7. The turbomachine according to claim 6, wherein said holding means comprises a projection extending radially inward from at least one of said ring holes, said projection adapted to be disposed between one of said attaching means and said flange.   
     
     
       8. The turbomachine according to claim 1, further comprising means for radially locating said ring with respect to said flange. 
     
     
       9. The turbomachine according to claim 8, wherein said flange has an outward face, and wherein said locating means comprises: a) a circumferential groove formed in said flange face; and   b) a spigot formed on said ring adapted to engage said groove.   
     
     
       10. The turbomachine according to claim 1, wherein said ring is formed by a plurality of arcuate segments. 
     
     
       11. In a steam turbine having a rotor having a plurality of fasteners arranged in a circumferential array, an apparatus for reducing the wind resistance associated with the motion of said fasteners as said rotor rotates, comprising a ring filling the circumferential space between each of said adjacent fasteners. 
     
     
       12. The apparatus according to claim 11, further comprising means for attaching and detaching said ring from said rotor. 
     
     
       13. The apparatus according to claim 11, wherein: a) said ring has a plurality of first holes for each of said fasteners extending partially therethrough and a second hole for each of said first holes, said second holes being substantially concentric with said first holes and having a smaller diameter, whereby an annular lip is formed between said first and second holes; and   b) said attaching and detaching means comprises said annular lip being disposed between said fasteners and said rotor.   
     
     
       14. The apparatus according to claim 11, wherein: a) said rotor has an outward radial face against which said ring bears;   b) each of said fasteners has a radial end face that extends a first distance beyond said rotor face in the axial direction; and   c) said ring has a radial end face that extends a second predetermined distance beyond said rotor face in the axial direction, said first and second distances being approximately equal; whereby said fastener means end faces and said ring end face form at least a first portion of a substantially smooth radial surface forming a boundary around said fastener means.     
     
     
       15. The apparatus according to claim 14, wherein each of said fasteners comprises a bolt and nut. 
     
     
       16. The apparatus according to claim 15, wherein each of said bolts has an end face, said bolt end faces forming a second portion of said substantially smooth boundary surface. 
     
     
       17. In a steam turbine having a rotor having a plurality of projections extending therefrom in a circumferential array, an attachable and detachable apparatus for reducing the wind resistance associated with the motion of said projections as said rotor rotates, comprising an arcuate member filling the circumferential space between each of said adjacent projections and forming radially and circumferentially extending surfaces substantially free of discontinuities, said surfaces forming an envelope enclosing each of said projections.